EFFECT OF ATMOSPHERIC PROPAGATION IN RCS PREDICTIONS

We consider how an electromagnetic fleld propagating to a target alters the radar cross section of the target relative to an observer. We derive the optimum high-frequency path for the flelds using the calculus of variations and by using a realistic refractive index proflle for the atmosphere obtain closed form solutions. It is found that the predicted nulls and peaks in the radar cross section of a scattering object relative to an observer are shifted from those normally expected from just the isolated object. Hence, for predictive purposes at least, radar cross section results need to incorporate the efiects of atmospheric propagation.